In the conventional type of an alarm wristwatch sound holes are provided in the back of the watchcase. However, with this construction such sound holes are mostly closed by engagement of the back of the watchcase with the surface of the arm on which the wristwatch is worn. Hence the intensity of the sound emitted by the alarm is greatly attenuated or muffled when the wristwatch is mounted on an arm.
On the other hand, it is undesirable to provide many sound holes in the wristwatch case since this results in decreasing the sound effect.